lewerenz



1 4 June 14,1927. A. LEWERENZ Re 6,65

msunmmzous swuca Original Filed May 2a. 192: z Shoots-Shoa 1 Invent OT; Arthur Lewerenz,

His Attor'heg.

r 16,654 June 1927' A. LEWERENZ Re INSTANTANEOUS SWITCH Original Filed May 28, 192:: z sheds-shes. 2

Inve ntor"; Arthur L.ewe'r-e'nz,

His Attor'neg Reissued June 14, 1927.

UNITED STATES PATENT orrlcs.

ARTHUR 'LEWEBENZ, OF BERLIN, GERMANY, ASSIGNOR TO THE FIRM SGHEBBIUS 8t BITTER, OF WANNSEE, NEAR BERLIN, GERMANY.

ms rm'rnmons swrrcn.

Original 10. 1,519,195, dated November 18,1924, Serial No. 842,099, filed May 28, 1998. Application for reissue illed April. 7, 1928. Serial No. 100,459.

I Small sizedswitches have been built already which work under the influence of the heat and which comprise a strip of sheet metal consistin of two metals possessing l difierent COEfiCIGH tS of expansion due .to heat. The movements made by these double metal strips when the temperature changes are infinitesimally small and extremely slow owingto slow admission of the heat so that duringthe interrupting of the circuit electricity flows still over for acertain time with production of sparks, whereby the contact parts of such switches are rapidly destroyed.

' ithv many switches of this type the danger is present that the circuit might be accidentally interrupted if the switch is shaken. Withthe switches of known type the distance for which, the switch travels'could .be made only disproportionately smallso that it was ,not possible to control higher voltages with such-switches owing to. the danger .of the untimely sparking over. 7 g

illormany devices, for instance of heatin apparatus of smaller size, the dimensions 0 the switch were far too great so that the heat capacity of the switch influencedunfavorably the distribution of the heat and consequently the accuracy of the regulation.

" 0 heat switchaccording to the present invention is an instantaneous switch and Fig. 1 shows in elevation switch according to the invention.

FFig. 2 is a. cross section on line II'-II of fiig. 3 is a part elevation of the instantan'eous switch shown in Fig. 1 much enlarged scale.

Figs. 4, 5 and fish i i ght y i fiedform 'offcons'truction 'ofan taneous switch.

Figs- 7 a d 8 show in sid 'el v tion front view respectively a'l constructional detail' of another form of construction. 1

In a casing an oscillablv mounted element, for instance an elastic bi-metal strip 2 is inserted at 3. The bi-metal stri consists of twodifi'erent kinds of metal, or instance, at the left of brass and at the right of iron. At the free endof the strip a kind of head 4 is formed, for instance by bending of the end 5 which has an indentation 6. At the one side of the 'casing'l a contact member, consisting of'a contact screw 7 with contact pin 8 is inserted'in the casing 1 insulated bvmeans of insulating disks 9, said contact member forming'an abutment for the bi-metal strip '2 at the one side, the abutment at the other side being formed by a screw 10. At the point where the contact pin 8 issituated a separate contact plate 11 is arranged on the bi-metal strip-in order to enmrea secure contact. The contact member 7 is connected with the one I pole of a source of current and the casing 1 is connected with the other pole of the source of current.

It is essential that in the casing l an elastic support, in the form of construction shown in Figs. 1-3 a helical or spiral spring 12, is arranged which acts upon the free end 4 of the elastic bi-metal strip 21 -and which is designed to reduce, at the liftin Qofthe bi-metal strip off the contact mem r'7 or ofi' the contact. pin 8 of the same the resistance against this liftin oil and, after the bi-metal strip has got eyond the middle position, to assist this lifting off so that the of the contact-is effected, instany and not slowly and lingering with opening taneous sparking over.

. The spiral spring lfi has at: each end a an'instantaneous sharp hardened point 13 and 14 engaging,

the one 13, wi th the indentation 6 of the bi-; metal strip and the other 14 with an indentation 15 ohm adjusting screw 16'.

13y adjusting the screw 16 the difierenoeg.

the switching out is altered, this difference) of temperature increasing with the ressure; .of the elastic support 12 upon the 4 of o'scillab e element 2. A

rature between the switching ill-Midi! endll rzgulat' screw-'8' is further provided, whi is $5 absolutely uniformly, viz,

signed to regulate the contact pressure between the bi-metal strip 2 and the contact pin 8 and to determine tlie degree of temperature at which the interruption of' contact has to take place.

The operation of the instantaneous switch isas follows:

Suppose the regulating screws 2 be tightened so that the bi-metal stri is in contact with the contactpin 8 of t e con-' tact member 7 with a determined pressure, the circuitbeing thus closed. The elastic support 12 exerts in this case a determined pressure on the strip approximately in the longitudinal direction of this stop whereby,

at the normal position, the contact pressure of the strip upon the contact pin 8 is increased. If the strip is heated the force which tends to lift the strip from the control in 8 will just overcome at a .determines moment the force of the elastic support 12, so that the strip 2 begins to lift offthe contact pin. During this lifting of the strip the component diminishes ;with which the elastic support acts in the sense of pressing the element 2 on the contact pin 8. This component will become zero at the instant when the oscillating element 2 moves through the middle position MM, and, if the movement of the oscillating element 2 continues, it will exert an increasing force which assists in the lifting of the element 2. The forces of the elastic support 2 acting upon the oscillating element 2 change roportionally to the displacement between the abutments.

Ex eriments with and without elastic sup port ave shown that the amplitude of the oscillating movement of; element 2 at equal differences of temperature is considerably greater if the elastic support 12 is inserted than without this support, provided the elastic amplitude of the oscillating element 2 and the pressure of the elastic support 12 are in a determined relation- This relation may be ascertained easily by adjusting the screw 16.

' In the form of construction shown in Fig. 4 an elastic bi-mctal strip 17 is used as oscillating element which is adapted to oscil late, same as in the form of construction shown in Figs. 1-3, between an adjustable contact member 18 and astop screw 19.

' A transverse beam 22 is mounted in a oneing 20 en a knife edge 21, a spring 23 act'- ing upon theends of said beam. The tension of the spring 23 may be varied by means of a screw 23. Between the free end of the bi-metal strip 17 and the transverse beam 22 a support 24, composed of steel blades or the like, is inserted withtheaid of knife edges so that it is freely movable.

The operation is similar to that described with reference. to Figs. 13.

According to Fig. 5 the oscillating elementconsists of an elastic strip 25. inserted in a casing 26 and adapted to oscillate between an adjustable contact member 27 and an adjustable stop 28. An elastic support 29 of similar construction as shown in Figs. 13 acts upon the free end of the oscillating element 25.

The oscillating element 25 is exposed on the one side to the action of---a spring 30 which has the tendency to press the oscillating element against the contact member and it'is onthe other side under the influence of i a wire 31 which is attached to a body possessing a dilferentcoeiticient of expansion. In the form of construction shown this wire, for instance a steel wire, is fixed to a'screw cap 32 of a brass tube '33 connected with the casing 26.

The lifting of the oscillating element25 i off the contact 27 is controlled by a force which results from the diflI'erence of the longitudinal expansion. of the steel wire .31 and of the brass tube 32 at increasing heating, the lifting off being facilitated in the manner described by the elastic support 29 and assisted in such a manner that the lifting 011:

takes place instantaneously.

In the form of construction shown in Fig. 6 an elastic bimetal strip in form of a spiral 34 is fixed with the one end in the casing 35. The other end of the bi-metal strip is attached to an oscillating element 37 mounted on a knife edge 36 and it has the tendency to press normally this element against a concontact member is in this manner also facilitated and assisted.

V The tension of the ela'stic support 45 and con'se uently the difference of temperature may e regulated also ,by means of a regulating screw 46.

The two stops for the oscillating element which are for instance formed by" the ends of the contact pin 8 and of the screw 10 (Fig. 3) are preferably arranged at both sides and at equal distances from the middle axis M-M, this being however not absolutely necessary as the distances of the strips may be unequal, the apparatus working even ifboth strips are situated at the same side of the middle axis.

-What I claim as new and desire to secure by Letters Patent of the United States, is

1. An instantaneous thermo-switch comrising a thermostatic strip arranged to flex in response to changes in temperature so as to occupy a given position at ordinary temperatures and to move away from said position upon an increase in temperature, elastic means arranged to apply a force to said strip tending to hold said element in said position but to decreasingly resist the movement of said strip away from said position, said elastic means having a single stationary point of support, and switching means oper v ated by said strip.

2. An instantaneous thermo-switoh comprising a thermostatic strip arranged to flex tion thereof moves between two positions, elastic means arranged to apply a force to said element tending to hold said strip in either one of said positions but to decreasingly resist the movement of said strip away from either position up to a certain point the other position, and switching means operated by said strip. 1

3. An instantaneous thermo-switch comprising a thermostatic strip having a fixed end and arranged to flex in response to changes in temperature so that its other end moves between two positions, a spring having a singlestationary point of support,

a pivotal connection between said spring and the movable end of said strip, said spring being arranged to apply a force tending to hold said movable end in either position but to decreasingly oppose the movement of said end away from either position up to a certain pointand then to assist the moveswitching means operated by said strip.

4. An instantaneous thermo-switch comprising a thermostatic strip having a. fixed portion and arranged to flex in res onse to changes in temperature so that anot er portion moves between two positions, .resilient means acting upon said strip to decreasing 1y resist the movement of said strip away from either position up to a certain point and thereafter to assist the movement of saidgstrip in either direction from said point to the other position, means for adjusting the tension of said resilient means to change the temperature setting, and switching means operated by said strip.

5. An instantaneous thermo-switch comprisin a bimetallic thermostatic strip arran e to flex uponehanges in temperature so is at a portion thereof moves between two positions, a? stationary support, a com ression spring provided with abutment earings on said support and said strip, said upon changes in temperature so that a pox and then to assist the movement of said .strip in either direction from said point to ment of said end to the other position, andspring bein arranged to apply a force tend-- ing. to hol said thermostat in either p051- tion but to decreasingly oppose, the movement of said strip away from either position up to a certain point and then to assist the movement of said strip to the other position, and switching means operated by said strip.

6. An instantaneous thermo-switch comprising a thermostatic strip having a fixed end and arranged to flex in response to changes in temperature so that its other end moves between two positions, a compression spring having a single stationary point of support, a pivotal connection between said spring and the movable end of said strip, said spring being arranged to apply a force tending to hold said movable end in either position but to decreasingly oppose the movement of said end away from either position upto a certain point and then to assist'the movement of said end to the other position, switching means operated by said strip, means for adjusting said spring to vary the range of temperature between movements of said strip from one position to the other, and means for adjusting said strip to move said range to a. higher or lower temperature as desired.

7. An instantaneous thermo-switch for electric lines comprising in combination, a contact member connected to onepole of a source of current, temperature responsive means connected to the other pole of the source of current and including a stripshaped switching element for closing and interrupting the circuit, pressed against said cont-act member at normal temperature by a force and being adapted tomove away from the contact member to overcome said force for interrupting the circuit at increasing temperature, an elastic support acting upon the free end of said switching element for assisting the latter to rapidly move away from the contact member only after said element has moved a certain distance awayfrom the contact member, and a stop for limiting the movement away from said member.

'8. An instantaneous thermo-switch f electric lines comprising in combination a contact member connected to one pole of a source of'current, an-elastic stripvclamped at one end and connected withthe other pole of the source of current, and pressed by spring power at normal temperature against the said cont-act member, said strip at increasing temperature being adapted to move away from the contact member for interrupting the circuit, an elastic support ar ranged appgoximately in the-place of said strip and acting upon the free end of the latter .for rapidly moving the strip away from the contact member only after said strip has moved a certain distance away from the contact member, means for regulat:

.a source of current, acontact pin on said screw, an elastic by-metal strip clamped at one-end and connected with the other poleof the source of current, said strip being resilient and pressing by its ownspring power at normal temperature against said contact pin, an adjustable stopfor limiting the oscillation of the by-metal strip, a spiral spring arranged approximately in alignment with the by-metal strip and having at each end a sharp point, a regulating screw having an indentation receiving one of the points of said spiral spring, a head at the free end of the by-metal strip having an in dentation receiving the other point of said spiral spring, said spiral'spring being adapted, to oppose the movement of the strip away from the contact pin to a certain point and to then assist the further movement of the stripaway from the contact pin.

10. A switch as claimed in claim 3 including means for pressing the by-metal strip against the contact pin.

11. An instantaneous thermo-switch for electric lines comprising in combination a contact screw connected with one pole of and away from said screw, :1 contact-plate on the free end of the strip pressed by the resiliencyof the latter at normal temperature against said contact pin, a spiral .spring arranged approximately in alignfree end of the by-metal strip having an indentation receiving the other point of said spiral spring, said spring being adapted to resist the movement of the strip away from the contact screw to a certain point and to assist the further movement of the strip away from this point, a screw sto for limiting the movement of the by-meta strip, and a screw for regulating the pressure with which said by-metal strip is pressed against said contact screw.

12. An instantaneous thermo-switch includinga contact member adapted to be con nected to' one pole of a source of current, temperature responsive means including an oscillating conductor strip adapted to be connected to the other pole of the source of current and to bear with its free end at normal temperature against the contact member, said temperature responsive means functioning to move the strip away from the contact member when the temperature increases, and resilient means engaging said strip and functioning to decreasingly resist the movement of the strip away from the contact member up to a certain point and then to rapidly move the strip away from this point.

In witness whereof, I have hereunto set my hand this 23rd day of March, 1926.

ARTHUR LEWERENZ.

- CERTIFICATE OF CORRECTION,

Reissue Patent No. 16,654.

Granted Jude-l4, 1927, to

ARTHUR LEWERENZ. p

Y It io herchy certiii cd that error appears" in t'heprinted specification of the ibove numbered patient requiring correction as follows: Page 3, line 11, claiin l, for the word "element" read "strip"; and that the said Letters Patent should be read with this correction therein that the name nay conform to. the record of the case in the Patent Office. g

Signed and sealed thin 2nd day of August, A, D. 1927.

M; J. Moore, Acting Commissioner of, Patents.

.a source of current, acontact pin on said screw, an elastic by-metal strip clamped at one-end and connected with the other poleof the source of current, said strip being resilient and pressing by its ownspring power at normal temperature against said contact pin, an adjustable stopfor limiting the oscillation of the by-metal strip, a spiral spring arranged approximately in alignment with the by-metal strip and having at each end a sharp point, a regulating screw having an indentation receiving one of the points of said spiral spring, a head at the free end of the by-metal strip having an in dentation receiving the other point of said spiral spring, said spiral'spring being adapted, to oppose the movement of the strip away from the contact pin to a certain point and to then assist the further movement of the stripaway from the contact pin.

10. A switch as claimed in claim 3 including means for pressing the by-metal strip against the contact pin.

11. An instantaneous thermo-switch for electric lines comprising in combination a contact screw connected with one pole of and away from said screw, :1 contact-plate on the free end of the strip pressed by the resiliencyof the latter at normal temperature against said contact pin, a spiral .spring arranged approximately in alignfree end of the by-metal strip having an indentation receiving the other point of said spiral spring, said spring being adapted to resist the movement of the strip away from the contact screw to a certain point and to assist the further movement of the strip away from this point, a screw sto for limiting the movement of the by-meta strip, and a screw for regulating the pressure with which said by-metal strip is pressed against said contact screw.

12. An instantaneous thermo-switch includinga contact member adapted to be con nected to' one pole of a source of current, temperature responsive means including an oscillating conductor strip adapted to be connected to the other pole of the source of current and to bear with its free end at normal temperature against the contact member, said temperature responsive means functioning to move the strip away from the contact member when the temperature increases, and resilient means engaging said strip and functioning to decreasingly resist the movement of the strip away from the contact member up to a certain point and then to rapidly move the strip away from this point.

In witness whereof, I have hereunto set my hand this 23rd day of March, 1926.

ARTHUR LEWERENZ.

- CERTIFICATE OF CORRECTION,

Reissue Patent No. 16,654.

Granted Jude-l4, 1927, to

ARTHUR LEWERENZ. p

Y It io herchy certiii cd that error appears" in t'heprinted specification of the ibove numbered patient requiring correction as follows: Page 3, line 11, claiin l, for the word "element" read "strip"; and that the said Letters Patent should be read with this correction therein that the name nay conform to. the record of the case in the Patent Office. g

Signed and sealed thin 2nd day of August, A, D. 1927.

M; J. Moore, Acting Commissioner of, Patents. 

